1. Field of the Invention
This invention relates to a process for manufacturing ornamental parts having a color similar to that of gold and offering excellent resistance to corrosion and wear, and also relates to an ion plating apparatus to be used therefor.
2. Background of the Invention
When a wear-resistant film is coated on surfaces of ornamental parts such as watch cases and glass frames, a dry process of ion plating has been used, instead of a wet process of electrochemical plating. The ion plating process permits coating not only metals such as Ni, Pd and Au but also compounds such as carbide and nitride. Especially, a titanium nitride film coated by ion plating exhibits a simulated gold color and excellent corrosion and wear resistance. Therefore, it has been in wide use for a process for manufacturing ornamental parts. The improvements thereon is described in U.S. Pat. No. 4,226,082. However, the titanium nitride film exhibits pale yellow or pale ocher, which is not a necessarily preferable color for ornamental parts.
It is, therefore, proposed to overcoat an extremely thin gold film on the surface of the titanium nitride film so as to produce a vivid color as a whole (see U.S. Pat. No. 4,252,862). In this case, the affinity at the interface between the titanium nitride film and the gold film, and the color reproducibility are of importance for the manufacturing technologies. But, the conventional processes are unsatisfactory in these respects.